Estimating the willingness-to-pay for restoring indigenous vegetation at selected sites in South Africa
- Authors: Tessendorf, Sharon Erica
- Date: 2007
- Subjects: Water resources development -- South Africa , Water-supply -- South Africa , Alien plants -- South Africa , Restoration ecology -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:8999 , http://hdl.handle.net/10948/617 , Water resources development -- South Africa , Water-supply -- South Africa , Alien plants -- South Africa , Restoration ecology -- South Africa
- Description: The Working for Water (WfW) Programme is a public works programme designed to clear South Africa of invasive alien vegetation and to restore lowwater consuming indigenous vegetation in the areas that have been cleared. Funds to clear alien invasives were initially secured on the basis that such a programme would increase water runoff, facilitate biodiversity and ecosystem functioning, and provide social benefits through job creation. The economic merits of the Programme, in terms of increased water yields, has been established in the Western Cape and KwaZulu-Natal, but questioned in the Eastern and Southern Cape. However, there are economic aspects of the studies carried out in the Eastern and Southern Cape that merit more attention than was given them; one of these being the issue of non-water benefits. Preliminary figures emanating from contingent valuation pilot studies conducted at six WfW projects sites indicated that one of these non-water benefits, namely the biodiversity and ecosystem resilience benefit, could be substantial. As such, the primary objective of the present study was to apply the contingent valuation method (CVM) to value people’s preference for indigenous vegetation. This value was intended to serve as a proxy for increased biodiversity and ecosystem resilience at three WfW sites. Despite the controversy surrounding the CVM, it has been found that it is a credible valuation tool. The CVM’s merits lie in its versatility and in the fact that it is the only method available which is capable of obtaining estimates of both nonuse and use values, thus making it applicable for valuing biodiversity. The primary aim of a CVM study is to determine an estimate of the total willingness-to-pay (WTP). In this study, the total WTP figure was calculated by multiplying the median WTP for the local WfW Programme by the total number of user households. The respective total WTP amounts are shown in Table 1. It was anticipated that respondents would be willing to pay more for the national WfW Programme, than for the less inclusive good (i.e. the local WfW Programme). The results correspond with this expectation at the Port Elizabeth and Underberg sites. However, due to strategic factors Worcester respondents were willing to pay more for the local WfW Programme than for the national Programme.
- Full Text:
- Date Issued: 2007
- Authors: Tessendorf, Sharon Erica
- Date: 2007
- Subjects: Water resources development -- South Africa , Water-supply -- South Africa , Alien plants -- South Africa , Restoration ecology -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:8999 , http://hdl.handle.net/10948/617 , Water resources development -- South Africa , Water-supply -- South Africa , Alien plants -- South Africa , Restoration ecology -- South Africa
- Description: The Working for Water (WfW) Programme is a public works programme designed to clear South Africa of invasive alien vegetation and to restore lowwater consuming indigenous vegetation in the areas that have been cleared. Funds to clear alien invasives were initially secured on the basis that such a programme would increase water runoff, facilitate biodiversity and ecosystem functioning, and provide social benefits through job creation. The economic merits of the Programme, in terms of increased water yields, has been established in the Western Cape and KwaZulu-Natal, but questioned in the Eastern and Southern Cape. However, there are economic aspects of the studies carried out in the Eastern and Southern Cape that merit more attention than was given them; one of these being the issue of non-water benefits. Preliminary figures emanating from contingent valuation pilot studies conducted at six WfW projects sites indicated that one of these non-water benefits, namely the biodiversity and ecosystem resilience benefit, could be substantial. As such, the primary objective of the present study was to apply the contingent valuation method (CVM) to value people’s preference for indigenous vegetation. This value was intended to serve as a proxy for increased biodiversity and ecosystem resilience at three WfW sites. Despite the controversy surrounding the CVM, it has been found that it is a credible valuation tool. The CVM’s merits lie in its versatility and in the fact that it is the only method available which is capable of obtaining estimates of both nonuse and use values, thus making it applicable for valuing biodiversity. The primary aim of a CVM study is to determine an estimate of the total willingness-to-pay (WTP). In this study, the total WTP figure was calculated by multiplying the median WTP for the local WfW Programme by the total number of user households. The respective total WTP amounts are shown in Table 1. It was anticipated that respondents would be willing to pay more for the national WfW Programme, than for the less inclusive good (i.e. the local WfW Programme). The results correspond with this expectation at the Port Elizabeth and Underberg sites. However, due to strategic factors Worcester respondents were willing to pay more for the local WfW Programme than for the national Programme.
- Full Text:
- Date Issued: 2007
The role of acute toxicity data for South African freshwater macroinvertebrates in the derivation of water quality guidelines for salinity
- Authors: Browne, Samantha
- Date: 2005
- Subjects: Water-supply -- South Africa , Water quality management -- South Africa , Aquatic ecology -- South Africa , Ecosystem management -- South Africa , Freshwater invertebrates -- South Africa -- Ecology , Water -- Toxicology -- South Africa , Water quality biological assessment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4742 , http://hdl.handle.net/10962/d1006173 , Water-supply -- South Africa , Water quality management -- South Africa , Aquatic ecology -- South Africa , Ecosystem management -- South Africa , Freshwater invertebrates -- South Africa -- Ecology , Water -- Toxicology -- South Africa , Water quality biological assessment
- Description: Water resources are under ever-increasing pressure to meet the demands of various water users both nationally and internationally. The process of anthropogenically-induced salinisation serves to exacerbate this pressure by limiting the quantity and quality of water available for future use. Water quality guidelines provide the numerical goals which water resource managers can use to adequately manage and protect aquatic ecosystems. Various methods which have been developed and used internationally to derive such guidelines are discussed. Acute toxicity tests were conducted using two inorganic salts, NaCl and Na₂SO₄. Field collected, indigenous, freshwater macroinvertebrates were used as tests organisms. Data generated from these tests contributed to the expansion of the currently limited toxicological database of response data for indigenous organisms and the suitability of using such organisms for future testing was discussed. Salt sensitivities of indigenous freshwater invertebrates were compared those of species sourced from an international toxicological database and were found to have similar ranges of tolerances to NaCl and Na₂SO₄. Species sensitivity distributions (SSDs), a method of data extrapolation, were derived using different types of toxicological data, and hence different guideline values or protective concentrations were derived. These concentrations were equated to boundary values for South Africa’s ecological Reserve categories, which are used to describe degrees of health for aquatic ecosystems. Provisional results suggest that using only acute toxicity data in guideline derivation provides ecosystem protection that is under-protective. Chronic toxicity data, which include endpoints other than mortality, provide the most realistic environmental protection but lack data confidence due to small sample sizes (acute tests are more readily conducted than chronic tests). The potential contribution of sub-chronic data to guideline derivation is highlighted as these data are more readily extrapolated to chronic endpoints than acute data and sub-chronic tests are not as complex and demanding to conduct as chronic tests.
- Full Text:
- Date Issued: 2005
- Authors: Browne, Samantha
- Date: 2005
- Subjects: Water-supply -- South Africa , Water quality management -- South Africa , Aquatic ecology -- South Africa , Ecosystem management -- South Africa , Freshwater invertebrates -- South Africa -- Ecology , Water -- Toxicology -- South Africa , Water quality biological assessment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4742 , http://hdl.handle.net/10962/d1006173 , Water-supply -- South Africa , Water quality management -- South Africa , Aquatic ecology -- South Africa , Ecosystem management -- South Africa , Freshwater invertebrates -- South Africa -- Ecology , Water -- Toxicology -- South Africa , Water quality biological assessment
- Description: Water resources are under ever-increasing pressure to meet the demands of various water users both nationally and internationally. The process of anthropogenically-induced salinisation serves to exacerbate this pressure by limiting the quantity and quality of water available for future use. Water quality guidelines provide the numerical goals which water resource managers can use to adequately manage and protect aquatic ecosystems. Various methods which have been developed and used internationally to derive such guidelines are discussed. Acute toxicity tests were conducted using two inorganic salts, NaCl and Na₂SO₄. Field collected, indigenous, freshwater macroinvertebrates were used as tests organisms. Data generated from these tests contributed to the expansion of the currently limited toxicological database of response data for indigenous organisms and the suitability of using such organisms for future testing was discussed. Salt sensitivities of indigenous freshwater invertebrates were compared those of species sourced from an international toxicological database and were found to have similar ranges of tolerances to NaCl and Na₂SO₄. Species sensitivity distributions (SSDs), a method of data extrapolation, were derived using different types of toxicological data, and hence different guideline values or protective concentrations were derived. These concentrations were equated to boundary values for South Africa’s ecological Reserve categories, which are used to describe degrees of health for aquatic ecosystems. Provisional results suggest that using only acute toxicity data in guideline derivation provides ecosystem protection that is under-protective. Chronic toxicity data, which include endpoints other than mortality, provide the most realistic environmental protection but lack data confidence due to small sample sizes (acute tests are more readily conducted than chronic tests). The potential contribution of sub-chronic data to guideline derivation is highlighted as these data are more readily extrapolated to chronic endpoints than acute data and sub-chronic tests are not as complex and demanding to conduct as chronic tests.
- Full Text:
- Date Issued: 2005
An economic analysis of eradicating alien vegetation as an alternative to conventional water supply schemes: a case study of the Krom and Kouga
- Authors: Carpenter, Robert Charles
- Date: 1999
- Subjects: Alien plants -- South Africa , Water-supply -- South Africa , Kouga River (South Africa)
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1000 , http://hdl.handle.net/10962/d1002735 , Alien plants -- South Africa , Water-supply -- South Africa , Kouga River (South Africa)
- Description: South Africa is classified as an arid to semi-arid region and water scarcity in South Africa has been identified as a key factor limiting socioeconomic development in the next century. In the Algoa region, the total urban plus agricultural water demand is expected to exceed the supply by the year 2005. The Kouga Working for Water Project aims to increase the base flow to the existing dams which supply the Port Elizabeth metropolitan area through the eradication of invasive alien trees in the riparian areas of the Krom and Kouga catchments. This thesis analyses the economic efficiency of optimal catchment management as a water supply scheme. A cost-benefit analysis is conducted for the Kouga eradication programme, and its desirability is evaluated in terms of the net present value (NPV) and the internal rate of return (IRR) criteria. In order to compare the cost-e~i.ciency of the eradication programme to alternative water supply augmentation schemes the Unit Reference Value (URV) is calculated for the project. The NPV for the project is calculated using a discount rate of 7% and amounts to nearly R24 million. This positive NPV indicates that the project is economically desirable in that it results in the improvement of human welfare. The IRR decision rule supports this finding. The URV of the eradication scheme is found to be competitive to that generated by more conventional schemes. Considered in the evaluation of the project are a host of environmental benefits that accompany the eradication of alien vegetation. This is in contrast to alternative schemes which result in several detrimental impacts to the environment. The economic analysis concludes that the eradication of alien vegetation is an efficient and desirable alternative water supply augmentation scheme. The conclusions drawn from the analysis of the eradication programme in this catchment area can be extended to other catchment areas, with the aim of promoting the most efficient supply of water.
- Full Text:
- Date Issued: 1999
- Authors: Carpenter, Robert Charles
- Date: 1999
- Subjects: Alien plants -- South Africa , Water-supply -- South Africa , Kouga River (South Africa)
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1000 , http://hdl.handle.net/10962/d1002735 , Alien plants -- South Africa , Water-supply -- South Africa , Kouga River (South Africa)
- Description: South Africa is classified as an arid to semi-arid region and water scarcity in South Africa has been identified as a key factor limiting socioeconomic development in the next century. In the Algoa region, the total urban plus agricultural water demand is expected to exceed the supply by the year 2005. The Kouga Working for Water Project aims to increase the base flow to the existing dams which supply the Port Elizabeth metropolitan area through the eradication of invasive alien trees in the riparian areas of the Krom and Kouga catchments. This thesis analyses the economic efficiency of optimal catchment management as a water supply scheme. A cost-benefit analysis is conducted for the Kouga eradication programme, and its desirability is evaluated in terms of the net present value (NPV) and the internal rate of return (IRR) criteria. In order to compare the cost-e~i.ciency of the eradication programme to alternative water supply augmentation schemes the Unit Reference Value (URV) is calculated for the project. The NPV for the project is calculated using a discount rate of 7% and amounts to nearly R24 million. This positive NPV indicates that the project is economically desirable in that it results in the improvement of human welfare. The IRR decision rule supports this finding. The URV of the eradication scheme is found to be competitive to that generated by more conventional schemes. Considered in the evaluation of the project are a host of environmental benefits that accompany the eradication of alien vegetation. This is in contrast to alternative schemes which result in several detrimental impacts to the environment. The economic analysis concludes that the eradication of alien vegetation is an efficient and desirable alternative water supply augmentation scheme. The conclusions drawn from the analysis of the eradication programme in this catchment area can be extended to other catchment areas, with the aim of promoting the most efficient supply of water.
- Full Text:
- Date Issued: 1999
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